These analyzers are used in all sectors of activity: industrial, medical, food processing, etc., and concern all focused laser sources, already developed and being developed, that require complete characterization, and all the applications of focused laser treatments, among which mention may be made of:                drilling (percussion, trepanning),        welding,        cutting,        cladding,        fritting,        peening (imparting stress to a surface, destructive testing, adhesion testing, etc.),        surface treatment (cleaning, melting, etc.),        engraving or etching,        etc.        
Pulsed laser beam analysis is critical for evaluating laser irradiation conditions in the focal plane and on either side of the focal plane. These parameters are generally designated as follows:                the diameter of the beam approximated as a circular, elliptical, square, rectangular, etc. spot,        the intensity distribution over the zone irradiated by the laser,        the divergence of the focused beam (caustic focus),        the frequency: number of laser pulses per second,        the length of the pulses,        the temporal shape of the pulses,        the energy per pulse,        the peak power in the pulse,        the average power of the laser,        fluctuations pulse to pulse or in a train of pulses.        
At the present time no analyzer capable of extracting all of these parameters in the focal plane and on either side of the focal plane exists. In addition, existing instruments are confronted with difficulties with flux resistance (50 kW peak power), and with signal saturation at incident power densities above the saturation levels of the CCD or CMOS sensors used. As sensor saturation levels are about 0.5 μJ/cm2 at a wavelength of 1.064 μm, devices for sampling a portion of the beam are required to analyze it, and additional attenuators may also be required depending on the incident power density. In addition to being bulky, the attenuators used degrade the optical quality of the beam, making their use very debatable.
FIG. 1 shows a conventional analyzer designed to analyze focused laser beams. It comprises:                a convergent lens 3 called the shaping lens, of focal length f1, the object focal point of which must be placed in the focal plane 2 of the beam 1 to be analyzed,        a sampling and/or attenuating device 4 represented here by 3 prisms 41, 42, 43,        a device for absorbing energy, in this case a heat sink 8 (also designated a thermal joule meter) intended to absorb the unsampled beam, i.e. as much as more than 99.995% of the beam 1 to be analyzed,        a convergent lens 5, called the imaging lens, of focal length f2, which forms the image 11 of the beam at the focal plane 2 on the analyzing sensor 6, and which defines the magnification (f2/f1) applied when measuring the diameter of the focal plane: Øfocal=Øsensor×(f1/f2). A telescope may also be associated with this imaging lens, in order to increase magnification in the case where the laser beam to be analyzed has a small diameter (a few tens of microns),        a camera for analyzing images and therefore spatial energy distribution Ez(x,y): it is typically equipped with a CMOS or (windowless, in order to avoid problems with interference) CCD sensor 6 placed in the focal plane of the imaging lens 5.        
Prior to analysis of the beam, the shaping and imaging lenses 3, 5 are correctly positioned in order to guarantee measurement of the diameter of the image 11 of the beam obtained on the sensor 6. Manual adjustment of these lenses is difficult, and risks damaging the components of the device. Specifically, it is possible to accidentally focus the laser beam on internal components of the system, which may damage or destroy them despite the attenuation provided.
Furthermore, with a pulsed laser it is necessary to synchronize image capture with the incident laser pulses. This synchronization may be achieved if the laser has a “TRIGGER” output. However this operation may be expensive or even impossible, in certain cases, to implement.
All of these constraints mean that current beam analyzers are bulky, difficult to use, and fragile with respect to power density, or are even incapable of analyzing, for high-power laser beams (1 to 50 kW peak for a pulsed laser), all of the aforementioned characteristics.